Asymptotic improvements to quantum circuits via qutrits

Conference Paper

Quantum computation is traditionally expressed in terms of quantum bits, or qubits. In this work, we instead consider three-level qutrits. Past work with qutrits has demonstrated only constant factor improvements, owing to the log2(3) binary-to-ternary compression factor. We present a novel technique using qutrits to achieve a logarithmic depth (runtime) decomposition of the Generalized Toffoli gate using no ancilla-a significant improvement over linear depth for the best qubit-only equivalent. Our circuit construction also features a 70x improvement in two-qudit gate count over the qubit-only equivalent decomposition. This results in circuit cost reductions for important algorithms like quantum neurons and Grover search. We develop an open-source circuit simulator for qutrits, along with realistic near-term noise models which account for the cost of operating qutrits. Simulation results for these noise models indicate over 90% mean reliability (fidelity) for our circuit construction, versus under 30% for the qubit-only baseline. These results suggest that qutrits offer a promising path towards scaling quantum computation.

Full Text

Duke Authors

Cited Authors

  • Gokhale, P; Baker, JM; Duckering, C; Brown, NC; Brown, KR; Chong, FT

Published Date

  • June 22, 2019

Published In

Start / End Page

  • 554 - 566

International Standard Serial Number (ISSN)

  • 1063-6897

International Standard Book Number 13 (ISBN-13)

  • 9781450366694

Digital Object Identifier (DOI)

  • 10.1145/3307650.3322253

Citation Source

  • Scopus